Basis of presentation and significant accounting policies and practices - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Basic EPS:
Net income	$ 1,127	$ 1,722	$ 2,232	$ 3,430
Income allocated to RSUs	(6)	(9)	(11)	(17)
Income allocated to common stock	$ 1,121	$ 1,713	$ 2,221	$ 3,413
Weighted average number of shares outstanding, basic (in shares)	912	908	911	907
Basic (in dollars per share)	$ 1.23	$ 1.89	$ 2.44	$ 3.76
Dilutive effect of stock compensation plans (in shares)	7	8	7	9
Diluted EPS:
Net income	$ 1,127	$ 1,722	$ 2,232	$ 3,430
Income allocated to RSUs	(6)	(8)	(11)	(18)
Income allocated to common stock for diluted EPS	$ 1,121	$ 1,714	$ 2,221	$ 3,412
Weighted average number of shares outstanding, diluted (in shares)	919	916	918	916
Diluted (in dollars per share)	$ 1.22	$ 1.87	$ 2.42	$ 3.72